1. Field of the Invention
This invention relates to a tempo control apparatus which is capable of controlling the tempo of performance of a musical piece on real-time basis.
2. Prior Art
Conventionally, a tempo control apparatus has been in use, which controls the tempo of automatic performance of a musical piece on real-time basis according to the tempo of a tapping motion or a baton motion carried out by a player in a manner timed to each beat.
The conventional tempo control apparatus changes the tempo of performance of a musical piece merely by changing the time interval between two adjacent beats in response to the operation of the player. Therefore, to change the tempo of performance of a musical piece, the conventional tempo control apparatus has to change the tempo of performance of the musical piece in response to a tapping motion or a like tempo control operation every beat of the musical piece, irrespective of the player's skill. Generally, as the player is more skilled, he desires to control the tempo of performance with a timing shorter than the timing of each beat, e.g. with the timing of each note. However, the conventional tempo control apparatus cannot meet the player's desire.
The tempo control apparatus could be converted to one suitable for highly skilled players such that it can change the tempo with a timing shorter than the timing of one beat. Such a tempo control apparatus, however, does not suit beginners who are not skilled enough to control the tempo with such a short timing, making it impossible for them to properly control the tempo.
A tempo control apparatus which can control the tempo on real-time basis has been proposed by Japanese Laid-Open Patent Publication (Kokai) No. 6-27957 (hereinafter referred to as "the apparatus A"), which is adapted to start performance of a musical piece at an initial tempo set in advance, and then change the tempo in a manner following up the tempo control operation by the player.
Further, another tempo control system has been proposed by Japanese Patent Publication (Kokoku) No. 4-36398 (hereinafter referred to as "the apparatus B"), which is adapted to maintain a tempo having been set by manual control operation after the manual control operation is stopped, or return the tempo to a standard tempo when a tempo recovery switch is operated to inhibit the manual control operation and resume automatic tempo control.
However, the tempo control apparatus A always starts performance of a musical piece at the same initial tempo set in advance, which makes it impossible to set the tempo as desired by the player at the start of performance of the musical piece, which can result in that the player starts performance at an unstable tempo.
According to the tempo control apparatus B which maintains the tempo set by the manual control operation and forcibly recovers the standard tempo, such changing of the tempo is merely temporarily effected. That is, when the player operates the tempo control apparatus again, the tempo is changed according to his operation. More specifically, when the tempo control apparatus is operated again, the tempo is changed according to his operation irrespective of whether he intends to manually control the tempo or not. Thus, the player's intention does not necessarily reflect on the tempo. Further, when the standard tempo is recovered or the tempo is shifted from the standard tempo or the maintained tempo to a manually-controlled tempo, the tempo can be largely changed, resulting in unnatural reproduction of a musical piece.